$BTU
PEABODY ENERGY CORP Stock $btu

$btu Overview Financials Valuation SEC Filings Company Website

2019 Q4 Form 10-K Financial Statement

#000106472821000008 Filed on February 23, 2021

Income Statement

Concept	2019 Q4	2018 Q4	2018
Revenue	$1.117B	$1.397B	$5.582B
YoY Change	-20.02%	-7.91%	0.05%
Cost Of Revenue	$823.8M	$1.021B	$4.073B
YoY Change	-19.31%	-6.18%	1.02%
Gross Profit	$293.6M	$376.1M	$1.509B
YoY Change	-21.94%	-12.31%	-2.46%
Gross Profit Margin	26.28%	26.92%	27.04%
Selling, General & Admin	$51.00M	$53.50M	$158.1M
YoY Change	-4.67%	-5.31%	-20.31%
% of Gross Profit	17.37%	14.22%	10.48%
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$121.6M	$175.9M	$679.0M
YoY Change	-30.87%	-1.62%	5.85%
% of Gross Profit	41.42%	46.77%	44.99%
Operating Expenses	$172.6M	$229.4M	$158.1M
YoY Change	-24.76%	20.67%	-80.11%
Operating Profit	-$165.5M	$126.8M	$661.6M
YoY Change	-230.52%	-46.9%	-12.08%
Interest Expense	$36.80M	$36.50M	$151.3M
YoY Change	0.82%	-431.82%	-288.42%
% of Operating Profit		28.79%	22.87%
Other Income/Expense, Net	-$72.20M	$121.0M	$107.4M
YoY Change	-159.67%
Pretax Income	-$270.2M	$220.6M	$664.1M
YoY Change	-222.48%	-25.57%	615.63%
Income Tax	$19.80M	-$22.40M	$18.40M
% Of Pretax Income		-10.15%	2.77%
Net Earnings	-$289.8M	$252.6M	$544.4M
YoY Change	-214.73%	-29.5%	17.94%
Net Earnings / Revenue	-25.94%	18.08%	9.75%
Basic Earnings Per Share			$4.50
Diluted Earnings Per Share	-$2.985M	$2.103M	$4.43
COMMON SHARES
Basic Shares Outstanding	97.30M shares	113.1M shares	119.3M shares
Diluted Shares Outstanding	97.30M shares	114.7M shares	2.100M shares

Balance Sheet

Concept	2019 Q4	2018 Q4	2018
SHORT-TERM ASSETS
Cash & Short-Term Investments	$732.0M	$982.0M	$982.0M
YoY Change	-25.46%	-2.96%	-2.96%
Cash & Equivalents	$732.2M	$1.017B	$982.0M
Short-Term Investments
Other Short-Term Assets	$220.7M	$243.1M	$243.0M
YoY Change	-9.21%	-27.43%	-27.46%
Inventory	$331.5M	$280.2M	$280.0M
Prepaid Expenses
Receivables	$329.5M	$450.4M	$450.0M
Other Receivables	$46.40M	$104.9M	$0.00
Total Short-Term Assets	$1.614B	$1.956B	$1.956B
YoY Change	-17.47%	-10.7%	-10.68%
LONG-TERM ASSETS
Property, Plant & Equipment	$4.679B	$5.207B	$5.207B
YoY Change	-10.14%	1.86%	1.86%
Goodwill
YoY Change
Intangibles
YoY Change
Long-Term Investments	$56.90M	$45.90M	$168.0M
YoY Change	23.97%	-88.2%	-56.81%
Other Assets	$139.1M	$212.6M	$49.00M
YoY Change	-34.57%	-48.02%	-88.02%
Total Long-Term Assets	$4.929B	$5.468B	$5.468B
YoY Change	-9.86%	-8.73%	-8.73%
TOTAL ASSETS
Total Short-Term Assets	$1.614B	$1.956B	$1.956B
Total Long-Term Assets	$4.929B	$5.468B	$5.468B
Total Assets	$6.543B	$7.424B	$7.424B
YoY Change	-11.87%	-9.26%	-9.25%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$810.0M		$282.0M
YoY Change			-27.32%
Accrued Expenses	$30.00M	$10.00M	$543.0M
YoY Change	200.0%	-9.09%	-9.5%
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due	$18.00M	$37.00M	$37.00M
YoY Change	-51.35%	-11.9%	-11.9%
Total Short-Term Liabilities	$975.3M	$1.059B	$1.059B
YoY Change	-7.86%	-14.98%	-14.94%
LONG-TERM LIABILITIES
Long-Term Debt	$1.293B	$1.331B	$1.331B
YoY Change	-2.85%	-6.2%	-6.2%
Other Long-Term Liabilities	$273.4M	$339.3M	$1.573B
YoY Change	-19.42%	-81.72%	-15.25%
Total Long-Term Liabilities	$273.4M	$339.3M	$2.904B
YoY Change	-19.42%	-89.64%	-11.33%
TOTAL LIABILITIES
Total Short-Term Liabilities	$975.3M	$1.059B	$1.059B
Total Long-Term Liabilities	$273.4M	$339.3M	$2.904B
Total Liabilities	$3.870B	$3.972B	$4.028B
YoY Change	-2.56%	-13.18%	-11.96%
SHAREHOLDERS EQUITY
Retained Earnings	$597.0M	$1.075B
YoY Change	-44.44%
Common Stock	$3.351B	$3.305B
YoY Change	1.4%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$1.367B	$1.025B
YoY Change	33.38%
Treasury Stock Shares	42.30M shares	27.30M shares
Shareholders Equity	$2.614B	$3.396B	$3.396B
YoY Change
Total Liabilities & Shareholders Equity	$6.543B	$7.424B	$7.424B
YoY Change	-11.87%	-9.26%	-9.25%

Cashflow Statement

Concept	2019 Q4	2018 Q4	2018
OPERATING ACTIVITIES
Net Income	-$289.8M	$252.6M	$544.4M
YoY Change	-214.73%	-29.5%	17.94%
Depreciation, Depletion And Amortization	$121.6M	$175.9M	$679.0M
YoY Change	-30.87%	-1.62%	5.85%
Cash From Operating Activities	$124.8M	$228.9M	$1.490B
YoY Change	-45.48%	-50.97%	47.32%
INVESTING ACTIVITIES
Capital Expenditures	-$102.6M	-$114.5M	$301.0M
YoY Change	-10.39%	16.84%	-250.95%
Acquisitions			$387.4M
YoY Change
Other Investing Activities	-$11.10M	-$337.3M	-$3.800M
YoY Change	-96.71%	-953.92%	-103.14%
Cash From Investing Activities	-$113.7M	-$451.8M	-$517.3M
YoY Change	-74.83%	672.31%	560.66%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net			$834.7M
YoY Change			-575.07%
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-91.30M	-162.1M	-$1.025B
YoY Change	-43.68%	-49.55%	29.26%
NET CHANGE
Cash From Operating Activities	124.8M	228.9M	$1.490B
Cash From Investing Activities	-113.7M	-451.8M	-$517.3M
Cash From Financing Activities	-91.30M	-162.1M	-$1.025B
Net Change In Cash	-80.20M	-385.0M	-$52.80M
YoY Change	-79.17%	-542.02%	-137.77%
FREE CASH FLOW
Cash From Operating Activities	$124.8M	$228.9M	$1.490B
Capital Expenditures	-$102.6M	-$114.5M	$301.0M
Free Cash Flow	$227.4M	$343.4M	$1.189B
YoY Change	-33.78%	-39.21%	-1.81%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2020	dei	Entity Central Index Key EntityCentralIndexKey	0001064728
CY2020	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2020
CY2020	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2020	dei	Amendment Flag AmendmentFlag	false
CY2019Q4	us-gaap	Operating Lease Liability Current Statement Of Financial Position Extensible List OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList	us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent
CY2020Q4	us-gaap	Operating Lease Liability Current Statement Of Financial Position Extensible List OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList	us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent
CY2020	dei	Document Type DocumentType	10-K
CY2020	dei	Document Annual Report DocumentAnnualReport	true
CY2020	dei	Document Period End Date DocumentPeriodEndDate	2020-12-31
CY2020	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2020	dei	Document Transition Report DocumentTransitionReport	false
CY2020	dei	Entity File Number EntityFileNumber	1-16463
CY2020	dei	Entity Registrant Name EntityRegistrantName	PEABODY ENERGY CORP
CY2020	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	DE
CY2020	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	13-4004153
CY2020	dei	Entity Address Address Line1 EntityAddressAddressLine1	701 Market Street,
CY2020	dei	Entity Address City Or Town EntityAddressCityOrTown	St. Louis,
CY2020	dei	Entity Address State Or Province EntityAddressStateOrProvince	MO
CY2020	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	63101-1826
CY2020	dei	City Area Code CityAreaCode	314
CY2020	dei	Local Phone Number LocalPhoneNumber	342-3400
CY2020	dei	Security12b Title Security12bTitle	Common Stock, par value $0.01 per share
CY2020	dei	Trading Symbol TradingSymbol	BTU
CY2020	dei	Security Exchange Name SecurityExchangeName	NYSE
CY2020	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	No
CY2020	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2020	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2020	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2020	dei	Entity Filer Category EntityFilerCategory	Accelerated Filer
CY2020	dei	Entity Small Business EntitySmallBusiness	false
CY2020	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2020	dei	Icfr Auditor Attestation Flag IcfrAuditorAttestationFlag	true
CY2020	dei	Entity Shell Company EntityShellCompany	false
CY2020Q2	dei	Entity Public Float EntityPublicFloat	196300000	USD
CY2020	dei	Entity Bankruptcy Proceedings Reporting Current EntityBankruptcyProceedingsReportingCurrent	true
CY2021Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	98244140	shares
CY2020	us-gaap	Revenues Revenues	2881100000	USD
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CY2020	us-gaap	Reorganization Items ReorganizationItems	0	USD
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CY2020Q4	us-gaap	Other Assets Current OtherAssetsCurrent	204700000	USD
CY2019Q4	us-gaap	Other Assets Current OtherAssetsCurrent	220700000	USD
CY2020Q4	us-gaap	Assets Current AssetsCurrent	1420300000	USD
CY2019Q4	us-gaap	Assets Current AssetsCurrent	1613900000	USD
CY2020Q4	btu	Property Plant And Equipment And Finance Lease Right Of Use Asset After Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	3051100000	USD
CY2019Q4	btu	Property Plant And Equipment And Finance Lease Right Of Use Asset After Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	4679100000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	49900000	USD
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	82400000	USD
CY2020Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	140900000	USD
CY2019Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	139100000	USD
CY2020Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	4900000	USD
CY2019Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	28300000	USD
CY2020Q4	us-gaap	Assets Assets	4667100000	USD
CY2019Q4	us-gaap	Assets Assets	6542800000	USD
CY2020Q4	us-gaap	Long Term Debt And Capital Lease Obligations Current LongTermDebtAndCapitalLeaseObligationsCurrent	44900000	USD
CY2019Q4	us-gaap	Long Term Debt And Capital Lease Obligations Current LongTermDebtAndCapitalLeaseObligationsCurrent	18300000	USD
CY2020Q4	us-gaap	Accounts Payable And Accrued Liabilities Current AccountsPayableAndAccruedLiabilitiesCurrent	745700000	USD
CY2019Q4	us-gaap	Accounts Payable And Accrued Liabilities Current AccountsPayableAndAccruedLiabilitiesCurrent	957000000.0	USD
CY2020Q4	us-gaap	Liabilities Current LiabilitiesCurrent	790600000	USD
CY2019Q4	us-gaap	Liabilities Current LiabilitiesCurrent	975300000	USD
CY2020Q4	us-gaap	Long Term Debt And Capital Lease Obligations LongTermDebtAndCapitalLeaseObligations	1502900000	USD
CY2019Q4	us-gaap	Long Term Debt And Capital Lease Obligations LongTermDebtAndCapitalLeaseObligations	1292500000	USD
CY2020Q4	us-gaap	Deferred Income Tax Liabilities Net DeferredIncomeTaxLiabilitiesNet	35000000.0	USD
CY2019Q4	us-gaap	Deferred Income Tax Liabilities Net DeferredIncomeTaxLiabilitiesNet	28800000	USD
CY2020Q4	us-gaap	Asset Retirement Obligations Noncurrent AssetRetirementObligationsNoncurrent	650500000	USD
CY2019Q4	us-gaap	Asset Retirement Obligations Noncurrent AssetRetirementObligationsNoncurrent	654100000	USD
CY2020Q4	us-gaap	Other Postretirement Defined Benefit Plan Liabilities Noncurrent OtherPostretirementDefinedBenefitPlanLiabilitiesNoncurrent	413200000	USD
CY2019Q4	us-gaap	Other Postretirement Defined Benefit Plan Liabilities Noncurrent OtherPostretirementDefinedBenefitPlanLiabilitiesNoncurrent	593400000	USD
CY2020Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	42100000	USD
CY2019Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	52800000	USD
CY2020Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	251500000	USD
CY2019Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	273400000	USD
CY2020Q4	us-gaap	Liabilities Liabilities	3685800000	USD
CY2019Q4	us-gaap	Liabilities Liabilities	3870300000	USD
CY2020Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2019Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2020Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	450000000.0	shares
CY2019Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	450000000.0	shares
CY2020Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	140500000	shares
CY2020Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	97800000	shares
CY2019Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	139200000	shares
CY2019Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	96900000	shares
CY2020Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	3364600000	USD
CY2019Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	3351100000	USD
CY2020Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	42700000	shares
CY2019Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	42300000	shares
CY2020Q4	us-gaap	Treasury Stock Value TreasuryStockValue	1368900000	USD
CY2019Q4	us-gaap	Treasury Stock Value TreasuryStockValue	1367300000	USD
CY2020Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	-1273300000	USD
CY2019Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	597000000.0	USD
CY2020Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	205800000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	31600000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	929600000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	2613800000	USD
CY2020Q4	us-gaap	Minority Interest MinorityInterest	51700000	USD
CY2019Q4	us-gaap	Minority Interest MinorityInterest	58700000	USD
CY2020Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	981300000	USD
CY2019Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	2672500000	USD
CY2020Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	4667100000	USD
CY2019Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	6542800000	USD
CY2020	us-gaap	Profit Loss ProfitLoss	-1873800000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	-185100000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	663800000	USD
CY2020	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	-14000000.0	USD
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	3200000	USD
CY2018	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	18100000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	-1859800000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	-188300000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	645700000	USD
CY2020	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	346000000.0	USD
CY2019	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	601000000.0	USD
CY2018	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	679000000.0	USD
CY2020	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-16200000	USD
CY2019	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-16200000	USD
CY2018	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-19200000	USD
CY2020	us-gaap	Increase Decrease In Materials And Supplies IncreaseDecreaseInMaterialsAndSupplies	700000	USD
CY2019	us-gaap	Increase Decrease In Materials And Supplies IncreaseDecreaseInMaterialsAndSupplies	-8300000	USD
CY2018	us-gaap	Increase Decrease In Materials And Supplies IncreaseDecreaseInMaterialsAndSupplies	0	USD
CY2020	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	27800000	USD
CY2019	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	39400000	USD
CY2018	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	35500000	USD
CY2020	btu	Sharebased Compensation Total SharebasedCompensationTotal	13500000	USD
CY2019	btu	Sharebased Compensation Total SharebasedCompensationTotal	38300000	USD
CY2018	btu	Sharebased Compensation Total SharebasedCompensationTotal	34900000	USD
CY2020	us-gaap	Restructuring Costs And Asset Impairment Charges RestructuringCostsAndAssetImpairmentCharges	1487400000	USD
CY2019	us-gaap	Restructuring Costs And Asset Impairment Charges RestructuringCostsAndAssetImpairmentCharges	270200000	USD
CY2018	us-gaap	Restructuring Costs And Asset Impairment Charges RestructuringCostsAndAssetImpairmentCharges	0	USD
CY2020	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	15200000	USD
CY2019	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	2100000	USD
CY2018	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	48200000	USD
CY2020	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-60100000	USD
CY2019	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	3400000	USD
CY2018	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	68100000	USD
CY2020	btu	Provisionforequipmentloss Provisionforequipmentloss	0	USD
CY2019	btu	Provisionforequipmentloss Provisionforequipmentloss	83200000	USD
CY2018	btu	Provisionforequipmentloss Provisionforequipmentloss	66400000	USD
CY2020	btu	Gainon Veb Asettlement GainonVEBAsettlement	0	USD
CY2019	btu	Gainon Veb Asettlement GainonVEBAsettlement	48100000	USD
CY2018	btu	Gainon Veb Asettlement GainonVEBAsettlement	0	USD
CY2020	btu	Monetization Foreign Currency Hedge Positions MonetizationForeignCurrencyHedgePositions	-13000000.0	USD
CY2019	btu	Monetization Foreign Currency Hedge Positions MonetizationForeignCurrencyHedgePositions	5200000	USD
CY2018	btu	Monetization Foreign Currency Hedge Positions MonetizationForeignCurrencyHedgePositions	9100000	USD
CY2020	btu	Reorganization Items Noncash ReorganizationItemsNoncash	0	USD
CY2019	btu	Reorganization Items Noncash ReorganizationItemsNoncash	0	USD
CY2018	btu	Reorganization Items Noncash ReorganizationItemsNoncash	12800000	USD
CY2020	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	-84600000	USD
CY2019	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	-82900000	USD
CY2018	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	-171800000	USD
CY2020	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-70600000	USD
CY2019	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	61600000	USD
CY2018	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-50200000	USD
CY2020	us-gaap	Increase Decrease In Other Current Assets IncreaseDecreaseInOtherCurrentAssets	-21000000.0	USD
CY2019	us-gaap	Increase Decrease In Other Current Assets IncreaseDecreaseInOtherCurrentAssets	35600000	USD
CY2018	us-gaap	Increase Decrease In Other Current Assets IncreaseDecreaseInOtherCurrentAssets	30600000	USD
CY2020	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	-192400000	USD
CY2019	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	-118200000	USD
CY2018	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	-160200000	USD
CY2020	btu	Proceeds From Release Of Collateral ProceedsFromReleaseOfCollateral	-15000000.0	USD
CY2019	btu	Proceeds From Release Of Collateral ProceedsFromReleaseOfCollateral	0	USD
CY2018	btu	Proceeds From Release Of Collateral ProceedsFromReleaseOfCollateral	323100000	USD
CY2020	us-gaap	Increase Decrease In Asset Retirement Obligations IncreaseDecreaseInAssetRetirementObligations	22500000	USD
CY2019	us-gaap	Increase Decrease In Asset Retirement Obligations IncreaseDecreaseInAssetRetirementObligations	6600000	USD
CY2018	us-gaap	Increase Decrease In Asset Retirement Obligations IncreaseDecreaseInAssetRetirementObligations	5700000	USD
CY2020	us-gaap	Increase Decrease In Workers Compensation Liabilities IncreaseDecreaseInWorkersCompensationLiabilities	1800000	USD
CY2019	us-gaap	Increase Decrease In Workers Compensation Liabilities IncreaseDecreaseInWorkersCompensationLiabilities	5000000.0	USD
CY2018	us-gaap	Increase Decrease In Workers Compensation Liabilities IncreaseDecreaseInWorkersCompensationLiabilities	-1800000	USD
CY2020	us-gaap	Increase Decrease In Postretirement Obligations IncreaseDecreaseInPostretirementObligations	-12100000	USD
CY2019	us-gaap	Increase Decrease In Postretirement Obligations IncreaseDecreaseInPostretirementObligations	36800000	USD
CY2018	us-gaap	Increase Decrease In Postretirement Obligations IncreaseDecreaseInPostretirementObligations	-151100000	USD
CY2020	us-gaap	Increase Decrease In Pension Plan Obligations IncreaseDecreaseInPensionPlanObligations	-28400000	USD
CY2019	us-gaap	Increase Decrease In Pension Plan Obligations IncreaseDecreaseInPensionPlanObligations	-32500000	USD
CY2018	us-gaap	Increase Decrease In Pension Plan Obligations IncreaseDecreaseInPensionPlanObligations	-66900000	USD
CY2020	us-gaap	Other Operating Activities Cash Flow Statement OtherOperatingActivitiesCashFlowStatement	100000	USD
CY2019	us-gaap	Other Operating Activities Cash Flow Statement OtherOperatingActivitiesCashFlowStatement	2100000	USD
CY2018	us-gaap	Other Operating Activities Cash Flow Statement OtherOperatingActivitiesCashFlowStatement	16000000.0	USD
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	15000000.0	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	705400000	USD
CY2018	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	1516900000	USD
CY2020	us-gaap	Cash Provided By Used In Operating Activities Discontinued Operations CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations	-24700000	USD
CY2019	us-gaap	Cash Provided By Used In Operating Activities Discontinued Operations CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations	-28000000.0	USD
CY2018	us-gaap	Cash Provided By Used In Operating Activities Discontinued Operations CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations	-27200000	USD
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	-9700000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	677400000	USD
CY2018	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	1489700000	USD
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	191400000	USD
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	285400000	USD
CY2018	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	301000000.0	USD
CY2020	btu	Increase Decease In Accrued Liabilities Related To Capital Expenditures Investing Activities IncreaseDeceaseInAccruedLiabilitiesRelatedToCapitalExpendituresInvestingActivities	-6100000	USD
CY2019	btu	Increase Decease In Accrued Liabilities Related To Capital Expenditures Investing Activities IncreaseDeceaseInAccruedLiabilitiesRelatedToCapitalExpendituresInvestingActivities	100000	USD
CY2018	btu	Increase Decease In Accrued Liabilities Related To Capital Expenditures Investing Activities IncreaseDeceaseInAccruedLiabilitiesRelatedToCapitalExpendituresInvestingActivities	100000	USD
CY2020	btu	Federal Coal Lease Expenditure FederalCoalLeaseExpenditure	0	USD
CY2019	btu	Federal Coal Lease Expenditure FederalCoalLeaseExpenditure	0	USD
CY2018	btu	Federal Coal Lease Expenditure FederalCoalLeaseExpenditure	500000	USD
CY2020	us-gaap	Proceeds From Insurance Settlement Investing Activities ProceedsFromInsuranceSettlementInvestingActivities	0	USD
CY2019	us-gaap	Proceeds From Insurance Settlement Investing Activities ProceedsFromInsuranceSettlementInvestingActivities	23200000	USD
CY2018	us-gaap	Proceeds From Insurance Settlement Investing Activities ProceedsFromInsuranceSettlementInvestingActivities	0	USD
CY2020	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	27100000	USD
CY2019	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	30000000.0	USD
CY2018	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	76400000	USD
CY2020	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	0	USD
CY2019	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	2400000	USD
CY2018	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	387400000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Term Of Contract LesseeOperatingLeaseTermOfContract	P10Y
CY2020	btu	Contributions To Joint Ventures ContributionsToJointVentures	343000000.0	USD
CY2019	btu	Contributions To Joint Ventures ContributionsToJointVentures	419100000	USD
CY2018	btu	Contributions To Joint Ventures ContributionsToJointVentures	475300000	USD
CY2020	btu	Distributions From Joint Ventures DistributionsFromJointVentures	330300000	USD
CY2019	btu	Distributions From Joint Ventures DistributionsFromJointVentures	408800000	USD
CY2018	btu	Distributions From Joint Ventures DistributionsFromJointVentures	483700000	USD
CY2020	us-gaap	Increase Decrease In Due From Related Parties IncreaseDecreaseInDueFromRelatedParties	23200000	USD
CY2019	us-gaap	Increase Decrease In Due From Related Parties IncreaseDecreaseInDueFromRelatedParties	27300000	USD
CY2018	us-gaap	Increase Decrease In Due From Related Parties IncreaseDecreaseInDueFromRelatedParties	13800000	USD
CY2020	us-gaap	Increase Decrease In Due To Related Parties IncreaseDecreaseInDueToRelatedParties	0	USD
CY2019	us-gaap	Increase Decrease In Due To Related Parties IncreaseDecreaseInDueToRelatedParties	14700000	USD
CY2018	us-gaap	Increase Decrease In Due To Related Parties IncreaseDecreaseInDueToRelatedParties	106700000	USD
CY2020	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	0	USD
CY2019	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	3000000.0	USD
CY2018	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	10000000.0	USD
CY2020	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	400000	USD
CY2019	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	900000	USD
CY2018	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-3800000	USD
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-206700000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-261300000	USD
CY2018	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-517300000	USD
CY2020	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	375000000.0	USD
CY2019	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	0	USD
CY2018	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	0	USD
CY2020	us-gaap	Repayments Of Long Term Debt And Capital Securities RepaymentsOfLongTermDebtAndCapitalSecurities	169500000	USD
CY2019	us-gaap	Repayments Of Long Term Debt And Capital Securities RepaymentsOfLongTermDebtAndCapitalSecurities	71100000	USD
CY2018	us-gaap	Repayments Of Long Term Debt And Capital Securities RepaymentsOfLongTermDebtAndCapitalSecurities	85000000.0	USD
CY2020	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	7000000.0	USD
CY2019	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	6400000	USD
CY2018	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	21200000	USD
CY2020	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	0	USD
CY2019	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	329900000	USD
CY2020	btu	Minimum Annual Production Of Federal Coal Mining Leases On Original Amount MinimumAnnualProductionOfFederalCoalMiningLeasesOnOriginalAmount	0.010
CY2018	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	834700000	USD
CY2020	btu	Payments For Repurchase Of Common Stock Relinquished For Tax Withholding PaymentsForRepurchaseOfCommonStockRelinquishedForTaxWithholding	1600000	USD
CY2019	btu	Payments For Repurchase Of Common Stock Relinquished For Tax Withholding PaymentsForRepurchaseOfCommonStockRelinquishedForTaxWithholding	12300000	USD
CY2018	btu	Payments For Repurchase Of Common Stock Relinquished For Tax Withholding PaymentsForRepurchaseOfCommonStockRelinquishedForTaxWithholding	14500000	USD
CY2020	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	0	USD
CY2019	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	258100000	USD
CY2018	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	59600000	USD
CY2020	btu	Minority Interest Increase From Contributions To Noncontrolling Interest Holders MinorityInterestIncreaseFromContributionsToNoncontrollingInterestHolders	3500000	USD
CY2019	btu	Minority Interest Increase From Contributions To Noncontrolling Interest Holders MinorityInterestIncreaseFromContributionsToNoncontrollingInterestHolders	23500000	USD
CY2018	btu	Minority Interest Increase From Contributions To Noncontrolling Interest Holders MinorityInterestIncreaseFromContributionsToNoncontrollingInterestHolders	10300000	USD
CY2020	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	0	USD
CY2019	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	0	USD
CY2018	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	100000	USD
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	193400000	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-701300000	USD
CY2018	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-1025200000	USD
CY2020	btu	Monthlyfederalroyaltiespayablefromsaleusingsurfaceminingmethods Monthlyfederalroyaltiespayablefromsaleusingsurfaceminingmethods	0.125
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-23000000.0	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-285200000	USD
CY2018	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-52800000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	732200000	USD
CY2018Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	1017400000	USD
CY2017Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	1070200000	USD
CY2020Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	709200000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	732200000	USD
CY2018Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	1017400000	USD
CY2017Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	3655800000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	663800000	USD
CY2018	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.485
CY2018	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	59600000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	-7100000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-44600000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-5900000	USD
CY2020	btu	Monthlyfederalroyaltiespayableofproductionusingundergroundminingmethods Monthlyfederalroyaltiespayableofproductionusingundergroundminingmethods	0.080
CY2018	us-gaap	Stock Issued During Period Value Conversion Of Convertible Securities StockIssuedDuringPeriodValueConversionOfConvertibleSecurities	0	USD
CY2018	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	34900000	USD
CY2018	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	834700000	USD
CY2018	us-gaap	Adjustments Related To Tax Withholding For Share Based Compensation AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation	14500000	USD
CY2018	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	10300000	USD
CY2018Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	3451600000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	-185100000	USD
CY2019	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	2.410
CY2019	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	258100000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	-0.0	USD
CY2019	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	8700000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	200000	USD
CY2019	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	38300000	USD
CY2019	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	329900000	USD
CY2019	us-gaap	Adjustments Related To Tax Withholding For Share Based Compensation AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation	12300000	USD
CY2019	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	23500000	USD
CY2019	btu	Foreign Currency Remeasurement Gains Losses ForeignCurrencyRemeasurementGainsLosses	-2700000	USD
CY2019Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	2672500000	USD
CY2020	us-gaap	Profit Loss ProfitLoss	-1873800000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	-0.0	USD
CY2020	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-168100000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	6100000	USD
CY2020	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	13500000	USD
CY2020	us-gaap	Adjustments Related To Tax Withholding For Share Based Compensation AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation	1600000	USD
CY2020	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	3500000	USD
CY2020Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	981300000	USD
CY2020Q3	btu	Contribution Amount To Co Issuers ContributionAmountToCoIssuers	100000000.0	USD
CY2020Q3	btu	Contribution To Co Issuers Period With Capital Needs ContributionToCoIssuersPeriodWithCapitalNeeds	P12M
CY2020	btu	Capitalized Debt Issuance Costs Related To Refinancing Transactions CapitalizedDebtIssuanceCostsRelatedToRefinancingTransactions	7000000.0	USD
CY2018	us-gaap	Gain Loss Related To Litigation Settlement GainLossRelatedToLitigationSettlement	12800000	USD
CY2020	btu	Accounts Receivable Payment Term AccountsReceivablePaymentTerm	P30D
CY2018	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	0	USD
CY2020	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	0	USD
CY2019	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	0	USD
CY2020	us-gaap	Royalty Expense RoyaltyExpense	214700000	USD
CY2019	us-gaap	Royalty Expense RoyaltyExpense	388600000	USD
CY2018	us-gaap	Royalty Expense RoyaltyExpense	474300000	USD
CY2019	us-gaap	Equity Method Investment Other Than Temporary Impairment EquityMethodInvestmentOtherThanTemporaryImpairment	0	USD
CY2020	us-gaap	Equity Method Investment Other Than Temporary Impairment EquityMethodInvestmentOtherThanTemporaryImpairment	0	USD
CY2018	us-gaap	Equity Method Investment Other Than Temporary Impairment EquityMethodInvestmentOtherThanTemporaryImpairment	0	USD
CY2019	us-gaap	Impairment Of Investments ImpairmentOfInvestments	9000000.0	USD
CY2018	us-gaap	Impairment Of Investments ImpairmentOfInvestments	0	USD
CY2020	us-gaap	Impairment Of Investments ImpairmentOfInvestments	0	USD
CY2020	us-gaap	Restructuring Charges RestructuringCharges	37900000	USD
CY2019	us-gaap	Restructuring Charges RestructuringCharges	24300000	USD
CY2018	us-gaap	Restructuring Charges RestructuringCharges	1200000	USD
CY2020Q4	us-gaap	Restructuring Reserve Current RestructuringReserveCurrent	2400000	USD
CY2020	us-gaap	Tangible Asset Impairment Charges TangibleAssetImpairmentCharges	1487400000	USD
CY2019	us-gaap	Tangible Asset Impairment Charges TangibleAssetImpairmentCharges	261200000	USD
CY2018	us-gaap	Tangible Asset Impairment Charges TangibleAssetImpairmentCharges	0	USD
CY2020	btu	Foreign Currency Remeasurement Gains Losses ForeignCurrencyRemeasurementGainsLosses	-4000000.0	USD
CY2018	btu	Foreign Currency Remeasurement Gains Losses ForeignCurrencyRemeasurementGainsLosses	1400000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	6100000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	200000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-5900000	USD
CY2020	us-gaap	Use Of Estimates UseOfEstimates	<div style="margin-bottom:9pt;margin-top:9pt;text-align:justify"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9.5pt;font-style:italic;font-weight:700;line-height:120%">Use of Estimates in the Preparation of the Consolidated Financial Statements</span></div><div style="margin-bottom:9pt;margin-top:9pt;text-align:justify;text-indent:18pt"><span style="color:#000000;font-family:'Arial',sans-serif;font-size:9.5pt;font-weight:400;line-height:120%">These consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the U.S. (U.S. GAAP). In doing so, estimates and assumptions are made that affect the amounts reported in the consolidated financial statements and accompanying notes. These estimates are based on historical experience and on various other assumptions deemed reasonable under the circumstances, the results of which form the basis for making judgments about the carrying amounts of assets and liabilities that are not readily apparent from other sources. The Company’s actual results may differ materially from these estimates. Significant estimates inherent in the preparation of these consolidated financial statements include, but are not limited to, accounting for sales and cost recognition, postretirement benefit plans, environmental receivables and liabilities, asset retirement obligations, evaluation of long-lived assets for impairment, income taxes including deferred tax assets, fair value measurements and contingencies.</span></div>
CY2020	us-gaap	Revenues Revenues	2881100000	USD
CY2019	us-gaap	Revenues Revenues	4623400000	USD
CY2018	us-gaap	Revenues Revenues	5581800000	USD
CY2020	us-gaap	Revenues Revenues	2881100000	USD
CY2019	us-gaap	Revenues Revenues	4623400000	USD
CY2018	us-gaap	Revenues Revenues	5581800000	USD
CY2020Q4	us-gaap	Contract With Customer Liability ContractWithCustomerLiability	3500000000	USD
CY2020Q4	us-gaap	Revenue Remaining Performance Obligation Percentage RevenueRemainingPerformanceObligationPercentage	0.46
CY2020Q4	us-gaap	Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1	P12M
CY2020Q4	us-gaap	Receivables Net Current ReceivablesNetCurrent	180900000	USD
CY2019Q4	us-gaap	Receivables Net Current ReceivablesNetCurrent	283100000	USD
CY2020Q4	us-gaap	Other Receivables Net Current OtherReceivablesNetCurrent	63900000	USD
CY2019Q4	us-gaap	Other Receivables Net Current OtherReceivablesNetCurrent	46400000	USD
CY2020Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	244800000	USD
CY2019Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	329500000	USD
CY2020	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	0	USD
CY2019	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	-4400000	USD
CY2018	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	-200000	USD
CY2020	btu	Impairment Of Unallocated Coal Reserves ImpairmentOfUnallocatedCoalReserves	69300000	USD
CY2019	btu	Impairment Of Unallocated Coal Reserves ImpairmentOfUnallocatedCoalReserves	69200000	USD
CY2019	us-gaap	Impairment Of Investments ImpairmentOfInvestments	9000000.0	USD
CY2018	us-gaap	Asset Impairment Charges AssetImpairmentCharges	0	USD
CY2020Q4	btu	Assets Subject To Recoverability Review AssetsSubjectToRecoverabilityReview	1200000000	USD
CY2020	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	-14000000.0	USD
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	3200000	USD
CY2018	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	18100000	USD
CY2020	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	0	USD
CY2019	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	0	USD
CY2018	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	0	USD
CY2020Q4	us-gaap	Liabilities Of Disposal Group Including Discontinued Operation Current LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent	62300000	USD
CY2019Q4	us-gaap	Liabilities Of Disposal Group Including Discontinued Operation Current LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent	58800000	USD
CY2020Q4	us-gaap	Disposal Group Including Discontinued Operation Other Noncurrent Liabilities DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentLiabilities	91400000	USD
CY2019Q4	us-gaap	Disposal Group Including Discontinued Operation Other Noncurrent Liabilities DisposalGroupIncludingDiscontinuedOperationOtherNoncurrentLiabilities	105500000	USD
CY2020Q4	us-gaap	Liabilities Of Disposal Group Including Discontinued Operation LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation	153700000	USD
CY2019Q4	us-gaap	Liabilities Of Disposal Group Including Discontinued Operation LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation	164300000	USD
CY2015Q4	btu	Number Of Buyers NumberOfBuyers	2	buyer
CY2019	us-gaap	Loss Contingency Accrual Carrying Value Period Increase Decrease LossContingencyAccrualCarryingValuePeriodIncreaseDecrease	100000	USD
CY2020	btu	Amountcontributedtothe Combined Benefit Fund AmountcontributedtotheCombinedBenefitFund	1600000	USD
CY2019	btu	Amountcontributedtothe Combined Benefit Fund AmountcontributedtotheCombinedBenefitFund	1900000	USD
CY2018	btu	Amountcontributedtothe Combined Benefit Fund AmountcontributedtotheCombinedBenefitFund	2200000	USD
CY2020Q4	btu	Combined Benefit Fund Liability CombinedBenefitFundLiability	13200000	USD
CY2019Q4	btu	Combined Benefit Fund Liability CombinedBenefitFundLiability	15200000	USD
CY2020Q4	us-gaap	Inventory Raw Materials And Supplies Net Of Reserves InventoryRawMaterialsAndSuppliesNetOfReserves	102600000	USD
CY2019Q4	us-gaap	Inventory Raw Materials And Supplies Net Of Reserves InventoryRawMaterialsAndSuppliesNetOfReserves	116300000	USD
CY2020Q4	btu	Raw Coal RawCoal	70500000	USD
CY2019Q4	btu	Raw Coal RawCoal	85100000	USD
CY2020Q4	btu	Saleable Coal SaleableCoal	88500000	USD
CY2019Q4	btu	Saleable Coal SaleableCoal	130100000	USD
CY2020Q4	us-gaap	Inventory Net InventoryNet	261600000	USD
CY2019Q4	us-gaap	Inventory Net InventoryNet	331500000	USD
CY2020Q4	us-gaap	Equity Method Investments EquityMethodInvestments	24600000	USD
CY2019Q4	us-gaap	Equity Method Investments EquityMethodInvestments	56900000	USD
CY2020	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-60100000	USD
CY2019	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	3400000	USD
CY2018	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	68100000	USD
CY2020	us-gaap	Concentration Risk Credit Risk ConcentrationRiskCreditRisk	The Company’s policy is to independently evaluate each customer’s creditworthiness prior to entering into transactions and to regularly monitor the credit extended. If the Company engages in a transaction with a counterparty that does not meet its credit standards, the Company seeks to protect its position by requiring the counterparty to provide an appropriate credit enhancement. Also, when appropriate (as determined by its credit management function), the Company has taken steps to reduce its exposure to customers or counterparties whose credit has deteriorated and who may pose a higher risk of failure to perform under their contractual obligations. These steps include obtaining letters of credit or cash collateral (margin), requiring prepayments for shipments or the creation of customer trust accounts held for the Company’s benefit to serve as collateral in the event of a failure to pay or perform. To reduce its credit exposure related to trading and brokerage activities, the Company seeks to enter into netting agreements with counterparties that permit the Company to offset asset and liability positions with such counterparties and, to the extent required, the Company will post or receive margin amounts associated with exchange-cleared and certain OTC positions.
CY2020Q4	btu	Property Plant And Equipment And Finance Lease Right Of Use Asset Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization	1321300000	USD
CY2019Q4	btu	Property Plant And Equipment And Finance Lease Right Of Use Asset Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization	1409800000	USD
CY2020Q4	btu	Property Plant And Equipment And Finance Lease Right Of Use Asset After Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	3051100000	USD
CY2019Q4	btu	Property Plant And Equipment And Finance Lease Right Of Use Asset After Accumulated Depreciation And Amortization PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	4679100000	USD
CY2020Q4	btu	Coal Reserves CoalReserves	1500000000	USD
CY2019Q4	btu	Coal Reserves CoalReserves	2800000000	USD
CY2020Q4	btu	Coal Reserves Not Subject To Depletion CoalReservesNotSubjectToDepletion	100000000	USD
CY2019Q4	btu	Coal Reserves Not Subject To Depletion CoalReservesNotSubjectToDepletion	100000000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	-1771500000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	-374200000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	-43400000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	-80300000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	231900000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	707500000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	-1851800000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	-142300000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	664100000	USD
CY2020	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-23900000	USD
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-21500000	USD
CY2018	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-46800000	USD
CY2020	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	2400000	USD
CY2019	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	28400000	USD
CY2018	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	29800000	USD
CY2020	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	1700000	USD
CY2019	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	-300000	USD
CY2018	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	-100000	USD
CY2020	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	-19800000	USD
CY2019	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	6600000	USD
CY2018	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	-17100000	USD
CY2020	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	23400000	USD
CY2019	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	20300000	USD
CY2018	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	30400000	USD
CY2020	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	4400000	USD
CY2019	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	19300000	USD
CY2018	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	5700000	USD
CY2020	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	0	USD
CY2019	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-200000	USD
CY2018	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-600000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	27800000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	39400000	USD
CY2018	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	35500000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	8000000.0	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	46000000.0	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	18400000	USD
CY2020	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	-388900000	USD
CY2019	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	-29900000	USD
CY2018	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	139500000	USD
CY2020	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	410100000	USD
CY2019	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	-32000000.0	USD
CY2018	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	-284600000	USD
CY2020	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	0	USD
CY2019	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	0	USD
CY2018	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	9500000	USD
CY2020	btu	Changesintaxreserves Changesintaxreserves	-7700000	USD
CY2019	btu	Changesintaxreserves Changesintaxreserves	3000000.0	USD
CY2018	btu	Changesintaxreserves Changesintaxreserves	2100000	USD
CY2020	us-gaap	Income Tax Reconciliation Nondeductible Expense Depletion IncomeTaxReconciliationNondeductibleExpenseDepletion	-14500000	USD
CY2019	us-gaap	Income Tax Reconciliation Nondeductible Expense Depletion IncomeTaxReconciliationNondeductibleExpenseDepletion	-19300000	USD
CY2018	us-gaap	Income Tax Reconciliation Nondeductible Expense Depletion IncomeTaxReconciliationNondeductibleExpenseDepletion	-28500000	USD
CY2020	us-gaap	Income Tax Reconciliation Repatriation Of Foreign Earnings IncomeTaxReconciliationRepatriationOfForeignEarnings	0	USD
CY2019	us-gaap	Income Tax Reconciliation Repatriation Of Foreign Earnings IncomeTaxReconciliationRepatriationOfForeignEarnings	76100000	USD
CY2018	us-gaap	Income Tax Reconciliation Repatriation Of Foreign Earnings IncomeTaxReconciliationRepatriationOfForeignEarnings	0	USD
CY2020	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	16400000	USD
CY2019	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	45600000	USD
CY2018	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	97100000	USD
CY2020	btu	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncome	0	USD
CY2019	btu	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncome	6100000	USD
CY2018	btu	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncome	68200000	USD
CY2020	btu	Remeasurement Of Foreign Taxes RemeasurementOfForeignTaxes	2900000	USD
CY2019	btu	Remeasurement Of Foreign Taxes RemeasurementOfForeignTaxes	-100000	USD
CY2018	btu	Remeasurement Of Foreign Taxes RemeasurementOfForeignTaxes	-200000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Property Plant And Equipment DeferredTaxAssetsPropertyPlantAndEquipment	573700000	USD
CY2020	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	-6800000	USD
CY2019	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	-13200000	USD
CY2018	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	3200000	USD
CY2020	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-3500000	USD
CY2019	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	9700000	USD
CY2018	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	12100000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	8000000.0	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	46000000.0	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	18400000	USD
CY2018	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	9500000	USD
CY2020	btu	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncome	0	USD
CY2019	btu	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncome	6100000	USD
CY2018	btu	Effective Income Tax Rate Reconciliation Global Intangible Low Taxed Income EffectiveIncomeTaxRateReconciliationGlobalIntangibleLowTaxedIncome	68200000	USD
CY2020	btu	Alternative Minimum Tax Credit Refunds Received AlternativeMinimumTaxCreditRefundsReceived	46900000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	1377400000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	1530900000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Property Plant And Equipment DeferredTaxAssetsPropertyPlantAndEquipment	276600000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Postretirement Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefits	93800000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Postretirement Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefits	142600000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Asset Retirement Obligations DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAssetRetirementObligations	95500000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Asset Retirement Obligations DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAssetRetirementObligations	86600000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits	22800000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits	25300000	USD
CY2020Q4	btu	Deferred Tax Asset Paymentstothe Veb Atosettletheaccumulatedpostretirementhealthcarebenefitobligations DeferredTaxAssetPaymentstotheVEBAtosettletheaccumulatedpostretirementhealthcarebenefitobligations	11000000.0	USD
CY2019Q4	btu	Deferred Tax Asset Paymentstothe Veb Atosettletheaccumulatedpostretirementhealthcarebenefitobligations DeferredTaxAssetPaymentstotheVEBAtosettletheaccumulatedpostretirementhealthcarebenefitobligations	12000000.0	USD
CY2020Q4	btu	Deferred Tax Assets Investmentsand Other Assets DeferredTaxAssetsInvestmentsandOtherAssets	88000000.0	USD
CY2019Q4	btu	Deferred Tax Assets Investmentsand Other Assets DeferredTaxAssetsInvestmentsandOtherAssets	89000000.0	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Compensation DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeCompensation	7800000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Compensation DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeCompensation	7600000	USD
CY2020Q4	btu	Deferred Tax Assets Operating Lease Liabilities DeferredTaxAssetsOperatingLeaseLiabilities	17500000	USD
CY2019Q4	btu	Deferred Tax Assets Operating Lease Liabilities DeferredTaxAssetsOperatingLeaseLiabilities	20800000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	24100000	USD
CY2019Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	140200000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	30100000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	16700000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	2311600000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	2208100000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	2287300000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	2068400000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	24300000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	139700000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	36200000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	100900000	USD
CY2020Q4	btu	Deferred Tax Liabilities Operating Lease Right Of Use Assets DeferredTaxLiabilitiesOperatingLeaseRightOfUseAssets	13500000	USD
CY2019Q4	btu	Deferred Tax Liabilities Operating Lease Right Of Use Assets DeferredTaxLiabilitiesOperatingLeaseRightOfUseAssets	20800000	USD
CY2020Q4	btu	Deferred Tax Liabilities Coal Supply Agreements DeferredTaxLiabilitiesCoalSupplyAgreements	3100000	USD
CY2019Q4	btu	Deferred Tax Liabilities Coal Supply Agreements DeferredTaxLiabilitiesCoalSupplyAgreements	3100000	USD
CY2020Q4	btu	Deferred Tax Liabilities Investments And Other Assets DeferredTaxLiabilitiesInvestmentsAndOtherAssets	1600000	USD
CY2019Q4	btu	Deferred Tax Liabilities Investments And Other Assets DeferredTaxLiabilitiesInvestmentsAndOtherAssets	15400000	USD
CY2020Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	54400000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	500000	USD
CY2020Q4	us-gaap	Deferred Income Taxes And Other Assets Noncurrent DeferredIncomeTaxesAndOtherAssetsNoncurrent	4900000	USD
CY2019Q4	us-gaap	Deferred Income Taxes And Other Assets Noncurrent DeferredIncomeTaxesAndOtherAssetsNoncurrent	28300000	USD
CY2020Q4	us-gaap	Deferred Income Taxes And Other Tax Liabilities Noncurrent DeferredIncomeTaxesAndOtherTaxLiabilitiesNoncurrent	35000000.0	USD
CY2019Q4	us-gaap	Deferred Income Taxes And Other Tax Liabilities Noncurrent DeferredIncomeTaxesAndOtherTaxLiabilitiesNoncurrent	28800000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	30100000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	500000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards Foreign DeferredTaxAssetsOperatingLossCarryforwardsForeign	2100000000	AUD
CY2020Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards Domestic DeferredTaxAssetsOperatingLossCarryforwardsDomestic	2800000000	USD
CY2020	btu	Operating Loss Carryforwards Increase Decrease OperatingLossCarryforwardsIncreaseDecrease	-1300000000	AUD
CY2020Q4	us-gaap	Tax Credit Carryforward Amount TaxCreditCarryforwardAmount	1400000000	USD
CY2020Q4	btu	Deferred Tax Assets Operating Loss Carryforwards Foreign Net DeferredTaxAssetsOperatingLossCarryforwardsForeignNet	590800000	USD
CY2020Q4	btu	Deferred Tax Assets Operating Loss Carryforwards Domestic Net DeferredTaxAssetsOperatingLossCarryforwardsDomesticNet	580300000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards State And Local DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal	76300000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards General Business DeferredTaxAssetsTaxCreditCarryforwardsGeneralBusiness	112600000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards Foreign DeferredTaxAssetsOperatingLossCarryforwardsForeign	15000000.0	USD
CY2020Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	2300000000	USD
CY2020Q4	btu	Unrecognized Tax Benefit Recordedin Deferred Income Taxes UnrecognizedTaxBenefitRecordedinDeferredIncomeTaxes	-7800000	USD
CY2019Q4	btu	Unrecognized Tax Benefit Recordedin Deferred Income Taxes UnrecognizedTaxBenefitRecordedinDeferredIncomeTaxes	-15500000	USD
CY2020Q4	btu	Unrecognized Tax Benefit Recordedin Other Noncurrent Liabilities UnrecognizedTaxBenefitRecordedinOtherNoncurrentLiabilities	1300000	USD
CY2019Q4	btu	Unrecognized Tax Benefit Recordedin Other Noncurrent Liabilities UnrecognizedTaxBenefitRecordedinOtherNoncurrentLiabilities	1000000.0	USD
CY2020Q4	btu	Net Unrecognized Tax Benefit NetUnrecognizedTaxBenefit	9100000	USD
CY2019Q4	btu	Net Unrecognized Tax Benefit NetUnrecognizedTaxBenefit	16500000	USD
CY2020Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	9100000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	16500000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Period Increase Decrease UnrecognizedTaxBenefitsPeriodIncreaseDecrease	-7400000	USD
CY2020Q4	btu	Net Unrecognized Tax Benefit NetUnrecognizedTaxBenefit	9100000	USD
CY2019Q4	btu	Net Unrecognized Tax Benefit NetUnrecognizedTaxBenefit	16500000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	16500000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	14000000.0	USD
CY2017Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	12700000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	1900000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	2200000	USD
CY2018	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	1800000	USD
CY2020	btu	Unrecognized Tax Benefits Increase Decrease Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreaseDecreaseResultingFromPriorPeriodTaxPositions	-9300000	USD
CY2019	btu	Unrecognized Tax Benefits Increase Decrease Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreaseDecreaseResultingFromPriorPeriodTaxPositions	300000	USD
CY2018	btu	Unrecognized Tax Benefits Increase Decrease Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreaseDecreaseResultingFromPriorPeriodTaxPositions	0	USD
CY2020	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	0	USD
CY2019	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	0	USD
CY2018	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	500000	USD
CY2020Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	9100000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	16500000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	14000000.0	USD
CY2018	btu	Unrecognized Tax Benefits Interest Tax Penalties And Interest Expense Reversal UnrecognizedTaxBenefitsInterestTaxPenaltiesAndInterestExpenseReversal	400000	USD
CY2019	btu	Unrecognized Tax Benefits Interest Tax Penalties And Interest Expense Reversal UnrecognizedTaxBenefitsInterestTaxPenaltiesAndInterestExpenseReversal	400000	USD
CY2020	btu	Unrecognized Tax Benefits Interest Tax Penalties And Interest Expense Reversal UnrecognizedTaxBenefitsInterestTaxPenaltiesAndInterestExpenseReversal	-400000	USD
CY2020Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	5400000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	5800000	USD
CY2020Q4	us-gaap	Decrease In Unrecognized Tax Benefits Is Reasonably Possible DecreaseInUnrecognizedTaxBenefitsIsReasonablyPossible	2200000	USD
CY2020	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	-39900000	USD
CY2019	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	-9100000	USD
CY2018	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	-64000000.0	USD
CY2020Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	163900000	USD
CY2019Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	186200000	USD
CY2020Q4	us-gaap	Accounts Payable Trade Current AccountsPayableTradeCurrent	146300000	USD
CY2019Q4	us-gaap	Accounts Payable Trade Current AccountsPayableTradeCurrent	254800000	USD
CY2020Q4	us-gaap	Other Accrued Liabilities Current OtherAccruedLiabilitiesCurrent	116200000	USD
CY2019Q4	us-gaap	Other Accrued Liabilities Current OtherAccruedLiabilitiesCurrent	118500000	USD
CY2020Q4	us-gaap	Accrual For Taxes Other Than Income Taxes Current AccrualForTaxesOtherThanIncomeTaxesCurrent	80400000	USD
CY2019Q4	us-gaap	Accrual For Taxes Other Than Income Taxes Current AccrualForTaxesOtherThanIncomeTaxesCurrent	99000000.0	USD
CY2020Q4	us-gaap	Long Term Debt And Capital Lease Obligations Current LongTermDebtAndCapitalLeaseObligationsCurrent	44900000	USD
CY2020Q4	us-gaap	Asset Retirement Obligation Current AssetRetirementObligationCurrent	77700000	USD
CY2019Q4	us-gaap	Asset Retirement Obligation Current AssetRetirementObligationCurrent	98200000	USD
CY2020Q4	us-gaap	Accrued Royalties Current AccruedRoyaltiesCurrent	25800000	USD
CY2019Q4	us-gaap	Accrued Royalties Current AccruedRoyaltiesCurrent	61700000	USD
CY2020Q4	us-gaap	Liabilities Of Disposal Group Including Discontinued Operation Current LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent	62300000	USD
CY2019Q4	us-gaap	Liabilities Of Disposal Group Including Discontinued Operation Current LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent	58800000	USD
CY2020Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	24500000	USD
CY2019Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	29600000	USD
CY2020Q4	btu	Accrued Health Care AccruedHealthCare	15700000	USD
CY2019Q4	btu	Accrued Health Care AccruedHealthCare	15800000	USD
CY2020Q4	us-gaap	Interest Payable Current InterestPayableCurrent	15500000	USD
CY2019Q4	us-gaap	Interest Payable Current InterestPayableCurrent	15000000.0	USD
CY2020Q4	us-gaap	Workers Compensation Liability Current WorkersCompensationLiabilityCurrent	9000000.0	USD
CY2019Q4	us-gaap	Workers Compensation Liability Current WorkersCompensationLiabilityCurrent	8400000	USD
CY2020Q4	btu	Finite Lived Intangible Liabilities FiniteLivedIntangibleLiabilities	4400000	USD
CY2019Q4	btu	Finite Lived Intangible Liabilities FiniteLivedIntangibleLiabilities	8400000	USD
CY2020Q4	us-gaap	Accrued Income Taxes Current AccruedIncomeTaxesCurrent	2300000	USD
CY2019Q4	us-gaap	Accrued Income Taxes Current AccruedIncomeTaxesCurrent	2600000	USD
CY2020Q4	btu	Liabilities From Coal Trading Activities Net LiabilitiesFromCoalTradingActivitiesNet	1700000	USD
CY2019Q4	btu	Liabilities From Coal Trading Activities Net LiabilitiesFromCoalTradingActivitiesNet	0	USD
CY2020Q4	us-gaap	Accounts Payable And Accrued Liabilities Current AccountsPayableAndAccruedLiabilitiesCurrent	745700000	USD
CY2019Q4	us-gaap	Accounts Payable And Accrued Liabilities Current AccountsPayableAndAccruedLiabilitiesCurrent	957000000.0	USD
CY2020Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	27300000	USD
CY2019Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	15200000	USD
CY2020Q4	us-gaap	Deferred Finance Costs Net DeferredFinanceCostsNet	42700000	USD
CY2019Q4	us-gaap	Deferred Finance Costs Net DeferredFinanceCostsNet	55500000	USD
CY2020Q4	us-gaap	Long Term Debt And Capital Lease Obligations Including Current Maturities LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities	1547800000	USD
CY2019Q4	us-gaap	Long Term Debt And Capital Lease Obligations Including Current Maturities LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities	1310800000	USD
CY2019Q4	us-gaap	Long Term Debt And Capital Lease Obligations Current LongTermDebtAndCapitalLeaseObligationsCurrent	18300000	USD
CY2020Q4	us-gaap	Long Term Debt And Capital Lease Obligations LongTermDebtAndCapitalLeaseObligations	1502900000	USD
CY2019Q4	us-gaap	Long Term Debt And Capital Lease Obligations LongTermDebtAndCapitalLeaseObligations	1292500000	USD
CY2020Q4	us-gaap	Line Of Credit Facility Remaining Borrowing Capacity LineOfCreditFacilityRemainingBorrowingCapacity	200000	USD
CY2020Q3	us-gaap	Proceeds From Accounts Receivable Securitization ProceedsFromAccountsReceivableSecuritization	60000000.0	USD
CY2020Q4	btu	Lease Obligation Assumed Amount Recoverablefrom Third Parties LeaseObligationAssumedAmountRecoverablefromThirdParties	0	USD
CY2020	us-gaap	Operating Lease Cost OperatingLeaseCost	28800000	USD
CY2019	us-gaap	Operating Lease Cost OperatingLeaseCost	43300000	USD
CY2020	us-gaap	Short Term Lease Cost ShortTermLeaseCost	39100000	USD
CY2019	us-gaap	Short Term Lease Cost ShortTermLeaseCost	49700000	USD
CY2020	us-gaap	Variable Lease Cost VariableLeaseCost	4600000	USD
CY2019	us-gaap	Variable Lease Cost VariableLeaseCost	19100000	USD
CY2020	btu	Sublease Expense Income SubleaseExpenseIncome	-2300000	USD
CY2019	btu	Sublease Expense Income SubleaseExpenseIncome	-2600000	USD
CY2020	us-gaap	Lease Cost LeaseCost	70200000	USD
CY2019	us-gaap	Lease Cost LeaseCost	109500000	USD
CY2020	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	3500000	USD
CY2019	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	15300000	USD
CY2020	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	800000	USD
CY2019	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	1500000	USD
CY2020	btu	Finance Lease Cost FinanceLeaseCost	4300000	USD
CY2019	btu	Finance Lease Cost FinanceLeaseCost	16800000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	49900000	USD
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	82400000	USD
CY2020Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	24500000	USD
CY2019Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	29600000	USD
CY2020Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	42100000	USD
CY2019Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	52800000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	66600000	USD
CY2019Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	82400000	USD
CY2020Q4	btu	Finance Lease Right Of Use Asset Before Accumulated Amortization FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization	20400000	USD
CY2019Q4	btu	Finance Lease Right Of Use Asset Before Accumulated Amortization FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization	89600000	USD
CY2020Q4	btu	Finance Lease Right Of Use Asset Accumulated Amortization FinanceLeaseRightOfUseAssetAccumulatedAmortization	2500000	USD
CY2019Q4	btu	Finance Lease Right Of Use Asset Accumulated Amortization FinanceLeaseRightOfUseAssetAccumulatedAmortization	45900000	USD
CY2020Q4	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	17900000	USD
CY2019Q4	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	43700000	USD
CY2020Q4	us-gaap	Finance Lease Liability Current FinanceLeaseLiabilityCurrent	21500000	USD
CY2019Q4	us-gaap	Finance Lease Liability Current FinanceLeaseLiabilityCurrent	14300000	USD
CY2020Q4	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	5800000	USD
CY2019Q4	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	900000	USD
CY2020Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	27300000	USD
CY2019Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	15200000	USD
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P3Y4M24D
CY2019Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P3Y9M18D
CY2020Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P9Y
CY2019Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P0Y7M6D
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.068
CY2019Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.073
CY2020Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.112
CY2019Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.060
CY2020	btu	Operatingcashflowsforoperatingleases Operatingcashflowsforoperatingleases	35100000	USD
CY2019	btu	Operatingcashflowsforoperatingleases Operatingcashflowsforoperatingleases	51000000.0	USD
CY2020	btu	Operatingcashflowsforfinanceleases Operatingcashflowsforfinanceleases	800000	USD
CY2019	btu	Operatingcashflowsforfinanceleases Operatingcashflowsforfinanceleases	1500000	USD
CY2020	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	8900000	USD
CY2019	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	29600000	USD
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	16500000	USD
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	16600000	USD
CY2020	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	1600000	USD
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	1600000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	24800000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Next Twelve Months FinanceLeaseLiabilityPaymentsDueNextTwelveMonths	17100000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	17600000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Year Two FinanceLeaseLiabilityPaymentsDueYearTwo	5800000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	16800000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Year Three FinanceLeaseLiabilityPaymentsDueYearThree	1500000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	6000000.0	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Year Four FinanceLeaseLiabilityPaymentsDueYearFour	700000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	3400000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Year Five FinanceLeaseLiabilityPaymentsDueYearFive	500000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	3800000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due After Year Five FinanceLeaseLiabilityPaymentsDueAfterYearFive	7700000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	72400000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due FinanceLeaseLiabilityPaymentsDue	33300000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	5800000	USD
CY2020Q4	us-gaap	Finance Lease Liability Undiscounted Excess Amount FinanceLeaseLiabilityUndiscountedExcessAmount	6000000.0	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	66600000	USD
CY2020Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	27300000	USD
CY2018	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	158000000.0	USD
CY2020	btu	Paid Discretionary Contributions To Defined Contribution Pension Plans Company Match PaidDiscretionaryContributionsToDefinedContributionPensionPlansCompanyMatch	9600000	USD
CY2019Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	752300000	USD
CY2018Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	750200000	USD
CY2020	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	38400000	USD
CY2019	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	47700000	USD
CY2020	us-gaap	Accretion Expense AccretionExpense	56000000.0	USD
CY2019	us-gaap	Accretion Expense AccretionExpense	54100000	USD
CY2020	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	-41700000	USD
CY2019	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	-4300000	USD
CY2020Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	728200000	USD
CY2019Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	752300000	USD
CY2020Q4	us-gaap	Asset Retirement Obligation Current AssetRetirementObligationCurrent	77700000	USD
CY2019Q4	us-gaap	Asset Retirement Obligation Current AssetRetirementObligationCurrent	98200000	USD
CY2020Q4	us-gaap	Asset Retirement Obligations Noncurrent AssetRetirementObligationsNoncurrent	650500000	USD
CY2019Q4	us-gaap	Asset Retirement Obligations Noncurrent AssetRetirementObligationsNoncurrent	654100000	USD
CY2020Q4	btu	Asset Retirement Obligation Active Locations AssetRetirementObligationActiveLocations	471800000	USD
CY2019Q4	btu	Asset Retirement Obligation Active Locations AssetRetirementObligationActiveLocations	525400000	USD
CY2020Q4	btu	Asset Retirement Obligation Closed Or Inactive Locations AssetRetirementObligationClosedOrInactiveLocations	256400000	USD
CY2019Q4	btu	Asset Retirement Obligation Closed Or Inactive Locations AssetRetirementObligationClosedOrInactiveLocations	226900000	USD
CY2020Q4	btu	Surety Bonds Outstanding For Reclamation SuretyBondsOutstandingForReclamation	1451900000	USD
CY2019Q4	btu	Surety Bonds Outstanding For Reclamation SuretyBondsOutstandingForReclamation	1401700000	USD
CY2020Q4	btu	Lettersofcreditinsupportofreclamationobligationsoractivities Lettersofcreditinsupportofreclamationobligationsoractivities	315000000.0	USD
CY2019Q4	btu	Lettersofcreditinsupportofreclamationobligationsoractivities Lettersofcreditinsupportofreclamationobligationsoractivities	106100000	USD
CY2020Q4	btu	Number Of Veba Trusts NumberOfVEBATrusts	2	numberOfTrust
CY2020Q4	us-gaap	Defined Benefit Plan Assets For Plan Benefits Noncurrent DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent	39600000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Assets For Plan Benefits Noncurrent DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent	13400000	USD
CY2017Q2	btu	Number Of Defined Contribution Plans NumberOfDefinedContributionPlans	3	numberOfPlan
CY2019	btu	Paid Discretionary Contributions To Defined Contribution Pension Plans Company Match PaidDiscretionaryContributionsToDefinedContributionPensionPlansCompanyMatch	27800000	USD
CY2018	btu	Paid Discretionary Contributions To Defined Contribution Pension Plans Company Match PaidDiscretionaryContributionsToDefinedContributionPensionPlansCompanyMatch	30300000	USD
CY2020	btu	Discretionarycontributionstodefinedcontributionpensionplansgranted Discretionarycontributionstodefinedcontributionpensionplansgranted	0	USD
CY2019	btu	Discretionarycontributionstodefinedcontributionpensionplansgranted Discretionarycontributionstodefinedcontributionpensionplansgranted	0	USD
CY2020	btu	Paymentofpriorperformancecontributions Paymentofpriorperformancecontributions	0	USD
CY2019	btu	Paymentofpriorperformancecontributions Paymentofpriorperformancecontributions	8900000	USD
CY2018	btu	Paymentofpriorperformancecontributions Paymentofpriorperformancecontributions	8500000	USD
CY2018	btu	Paymentofpriorperformancecontributions Paymentofpriorperformancecontributions	8500000	USD
CY2020Q4	btu	Common Stock Voting Rights Per Share CommonStockVotingRightsPerShare	1	numberOfVote
CY2019Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	96900000	shares
CY2018Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	110400000	shares
CY2017Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	105200000	shares
CY2020	us-gaap	Stock Issued During Period Shares Conversion Of Convertible Securities StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities	0	shares
CY2019	us-gaap	Stock Issued During Period Shares Conversion Of Convertible Securities StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities	0	shares
CY2018	us-gaap	Stock Issued During Period Shares Conversion Of Convertible Securities StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities	25500000	shares
CY2020	us-gaap	Stock Issued During Period Shares Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures	1300000	shares
CY2019	us-gaap	Stock Issued During Period Shares Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures	1500000	shares
CY2018	us-gaap	Stock Issued During Period Shares Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures	1100000	shares
CY2020	btu	Stock Issued During Period Shares Shares Issuedfor Disputed Claims StockIssuedDuringPeriodSharesSharesIssuedforDisputedClaims	0	shares
CY2019	btu	Stock Issued During Period Shares Shares Issuedfor Disputed Claims StockIssuedDuringPeriodSharesSharesIssuedforDisputedClaims	0	shares
CY2018	btu	Stock Issued During Period Shares Shares Issuedfor Disputed Claims StockIssuedDuringPeriodSharesSharesIssuedforDisputedClaims	100000	shares
CY2020	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	400000	shares
CY2019	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	15000000.0	shares
CY2018	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	21500000	shares
CY2020Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	97800000	shares
CY2019Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	96900000	shares
CY2018Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	110400000	shares
CY2020Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	100000000.0	shares
CY2017Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	13500000	shares
CY2018	us-gaap	Conversion Of Stock Shares Converted1 ConversionOfStockSharesConverted1	13500000	shares
CY2018Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	0	shares
CY2020Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	100000000.0	shares
CY2020Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	0	shares
CY2017Q3	us-gaap	Stock Repurchase Program Authorized Amount1 StockRepurchaseProgramAuthorizedAmount1	500000000.0	USD
CY2018Q2	us-gaap	Stock Repurchase Program Authorized Amount1 StockRepurchaseProgramAuthorizedAmount1	1000000000.0	USD
CY2018Q4	us-gaap	Stock Repurchase Program Authorized Amount1 StockRepurchaseProgramAuthorizedAmount1	1500000000	USD
	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	41500000	shares
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	1340300000	USD
CY2019	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	14600000	shares
CY2019	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	329900000	USD
CY2018	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	21100000	shares
CY2018	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	834700000	USD
	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	5800000	shares
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	175700000	USD
	us-gaap	Payments For Commissions PaymentsForCommissions	800000	USD
CY2020Q4	us-gaap	Stock Repurchase Program Remaining Authorized Repurchase Amount1 StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1	160500000	USD
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	13500000	USD
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	38300000	USD
CY2018	us-gaap	Share Based Compensation ShareBasedCompensation	34900000	USD
CY2020	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	0	USD
CY2019	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	0	USD
CY2018	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	0	USD
CY2020	btu	Share Based Compensation Expense Net Of Tax ShareBasedCompensationExpenseNetOfTax	13500000	USD
CY2019	btu	Share Based Compensation Expense Net Of Tax ShareBasedCompensationExpenseNetOfTax	38300000	USD
CY2018	btu	Share Based Compensation Expense Net Of Tax ShareBasedCompensationExpenseNetOfTax	34900000	USD
CY2020	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	0	USD
CY2019	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	0	USD
CY2018	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	0	USD
CY2020	btu	Write Off Tax Benefits Related To Share Based Compensation WriteOffTaxBenefitsRelatedToShareBasedCompensation	0	USD
CY2018	btu	Write Off Tax Benefits Related To Share Based Compensation WriteOffTaxBenefitsRelatedToShareBasedCompensation	0	USD
CY2020Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	13500000	USD
CY2020Q4	btu	Interestinunincorporatedjointventureproject Interestinunincorporatedjointventureproject	0.50
CY2020	us-gaap	Property Plant And Equipment Additions PropertyPlantAndEquipmentAdditions	72000000	USD
CY2019	btu	Write Off Tax Benefits Related To Share Based Compensation WriteOffTaxBenefitsRelatedToShareBasedCompensation	0	USD
CY2020	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1	P2Y
CY2020	btu	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition Weighted Average EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognitionWeightedAverage	P0Y8M12D
CY2020	btu	Number Of Mines Idled During Period NumberOfMinesIdledDuringPeriod	9	numberOfMine
CY2019	btu	Gainonformationof United Wambo Jv GainonformationofUnitedWamboJV	48100000	USD
CY2019	btu	Provisionforequipmentloss Provisionforequipmentloss	83200000	USD
CY2018	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	16900000	USD
CY2018	btu	Provisionforequipmentloss Provisionforequipmentloss	66400000	USD
CY2020	btu	Provisionforequipmentloss Provisionforequipmentloss	0	USD
CY2020	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	2200000	shares
CY2019	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	1900000	shares
CY2018	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	100000	shares
CY2020	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	-1859800000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	-188300000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	645700000	USD
CY2020	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	0	USD
CY2019	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	0	USD
CY2018	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	102500000	USD
CY2020	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	-3500000	USD
CY2019	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	26200000	USD
CY2020	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-1856300000	USD
CY2019	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-214500000	USD
CY2018	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	526300000	USD
CY2020	us-gaap	Participating Securities Distributed And Undistributed Earnings Loss Basic ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic	0	USD
CY2019	us-gaap	Participating Securities Distributed And Undistributed Earnings Loss Basic ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic	0	USD
CY2018	us-gaap	Participating Securities Distributed And Undistributed Earnings Loss Basic ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic	7900000	USD
CY2020	btu	Income From Continuing Operations Attributable To Common Stockholders IncomeFromContinuingOperationsAttributableToCommonStockholders	-1856300000	USD
CY2019	btu	Income From Continuing Operations Attributable To Common Stockholders IncomeFromContinuingOperationsAttributableToCommonStockholders	-214500000	USD
CY2018	btu	Income From Continuing Operations Attributable To Common Stockholders IncomeFromContinuingOperationsAttributableToCommonStockholders	518400000	USD
CY2020	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	-14000000.0	USD
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	3200000	USD
CY2018	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	18100000	USD
CY2020	btu	Lossfromdiscontinuedoperationsallocatedtoparticipatingsecurities Lossfromdiscontinuedoperationsallocatedtoparticipatingsecurities	0	USD
CY2019	btu	Lossfromdiscontinuedoperationsallocatedtoparticipatingsecurities Lossfromdiscontinuedoperationsallocatedtoparticipatingsecurities	0	USD
CY2018	btu	Lossfromdiscontinuedoperationsallocatedtoparticipatingsecurities Lossfromdiscontinuedoperationsallocatedtoparticipatingsecurities	300000	USD
CY2020	us-gaap	Net Income Loss From Discontinued Operations Available To Common Shareholders Basic NetIncomeLossFromDiscontinuedOperationsAvailableToCommonShareholdersBasic	-14000000.0	USD
CY2019	us-gaap	Net Income Loss From Discontinued Operations Available To Common Shareholders Basic NetIncomeLossFromDiscontinuedOperationsAvailableToCommonShareholdersBasic	3200000	USD
CY2018	us-gaap	Net Income Loss From Discontinued Operations Available To Common Shareholders Basic NetIncomeLossFromDiscontinuedOperationsAvailableToCommonShareholdersBasic	17800000	USD
CY2020	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	-1870300000	USD
CY2019	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	-211300000	USD
CY2018	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	536200000	USD
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	97700000	shares
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	103700000	shares
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	119300000	shares
CY2020	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	0	shares
CY2019	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	0	shares
CY2018	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	1700000	shares
CY2020	us-gaap	Weighted Average Number Of Share Outstanding Basic And Diluted WeightedAverageNumberOfShareOutstandingBasicAndDiluted	97700000	shares
CY2019	us-gaap	Weighted Average Number Of Share Outstanding Basic And Diluted WeightedAverageNumberOfShareOutstandingBasicAndDiluted	103700000	shares
CY2018	us-gaap	Weighted Average Number Of Share Outstanding Basic And Diluted WeightedAverageNumberOfShareOutstandingBasicAndDiluted	121000000.0	shares
CY2020	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-18.99
CY2019	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-2.07
CY2018	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	4.35
CY2020	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	-0.15
CY2019	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0.03
CY2018	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0.15
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-19.14
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-2.04
CY2018	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.50
CY2020	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-18.99
CY2019	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-2.07
CY2018	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	4.28
CY2020	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	-0.15
CY2019	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.03
CY2018	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.15
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-19.14
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-2.04
CY2018	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.43
CY2018	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	100000	USD
CY2018	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	2100000	shares
CY2020Q4	btu	Entity Number Of Hourly Employees EntityNumberOfHourlyEmployees	3500	numberOfEmployee
CY2020Q4	dei	Entity Number Of Employees EntityNumberOfEmployees	4600	numberOfEmployee
CY2020Q4	btu	Percentage Of Employees Represented By Organized Labor Unions PercentageOfEmployeesRepresentedByOrganizedLaborUnions	0.29
CY2020	btu	Percentage Of Coal Production Consolidated PercentageOfCoalProductionConsolidated	0.18
CY2020Q4	btu	Number Of Us Mines Represented By Unions NumberOfUsMinesRepresentedByUnions	1	numberOfMine
CY2020	btu	Period Of Agreement With Umwa Covering Hourly Coworkers Involved In Mining Reclamation PeriodOfAgreementWithUMWACoveringHourlyCoworkersInvolvedInMiningReclamation	P4Y
CY2020Q4	us-gaap	Letters Of Credit Outstanding Amount LettersOfCreditOutstandingAmount	437600000	USD
CY2020Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	728200000	USD
CY2020Q4	btu	Surety Bonds Outstanding For Reclamation SuretyBondsOutstandingForReclamation	1451900000	USD
CY2020Q4	btu	Lettersof Credit Outstandingfor Reclamation LettersofCreditOutstandingforReclamation	315000000.0	USD
CY2020	btu	Take Or Pay Arrangement Term TakeOrPayArrangementTerm	P22Y
CY2020Q4	btu	Take Or Pay Obligations Total TakeOrPayObligationsTotal	1200000000	USD
CY2020Q4	btu	Take Or Pay Obligations Due In One Year TakeOrPayObligationsDueInOneYear	95000000	USD
CY2020	us-gaap	Revenues Revenues	2881100000	USD
CY2020	btu	Segment Reporting Information Adjusted Earning Before Interest Taxes Depreciation And Amortization SegmentReportingInformationAdjustedEarningBeforeInterestTaxesDepreciationAndAmortization	258800000	USD
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	191400000	USD
CY2020	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-60100000	USD
CY2019	us-gaap	Revenues Revenues	4623400000	USD
CY2019	btu	Segment Reporting Information Adjusted Earning Before Interest Taxes Depreciation And Amortization SegmentReportingInformationAdjustedEarningBeforeInterestTaxesDepreciationAndAmortization	883000000.0	USD
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	285400000	USD
CY2019	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	3400000	USD
CY2018	us-gaap	Revenues Revenues	5581800000	USD
CY2018	btu	Segment Reporting Information Adjusted Earning Before Interest Taxes Depreciation And Amortization SegmentReportingInformationAdjustedEarningBeforeInterestTaxesDepreciationAndAmortization	1387900000	USD
CY2018	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	301000000.0	USD
CY2018	btu	Federal Coal Lease Expenditures FederalCoalLeaseExpenditures	500000	USD
CY2018	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	68100000	USD
CY2020Q4	us-gaap	Assets Assets	4667100000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	3051100000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	49900000	USD
CY2019Q4	us-gaap	Assets Assets	6542800000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	4679100000	USD
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	82400000	USD
CY2018Q4	us-gaap	Assets Assets	7423700000	USD
CY2018Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	5207000000.0	USD
CY2020	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	-1859800000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	-188300000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	645700000	USD
CY2020	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	346000000.0	USD
CY2019	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	601000000.0	USD
CY2018	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	679000000.0	USD
CY2020	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	45700000	USD
CY2019	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	58400000	USD
CY2018	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	53000000.0	USD
CY2020	us-gaap	Restructuring Charges RestructuringCharges	37900000	USD
CY2019	us-gaap	Restructuring Charges RestructuringCharges	24300000	USD
CY2018	us-gaap	Restructuring Charges RestructuringCharges	1200000	USD
CY2020	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	23100000	USD
CY2019	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	21600000	USD
CY2018	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	7400000	USD
CY2020	btu	Gainonformationof United Wambo Jv GainonformationofUnitedWamboJV	0	USD
CY2019	btu	Gainonformationof United Wambo Jv GainonformationofUnitedWamboJV	48100000	USD
CY2018	btu	Gainonformationof United Wambo Jv GainonformationofUnitedWamboJV	0	USD
CY2020	us-gaap	Asset Impairment Charges AssetImpairmentCharges	1487400000	USD
CY2019	us-gaap	Asset Impairment Charges AssetImpairmentCharges	270200000	USD
CY2018	us-gaap	Asset Impairment Charges AssetImpairmentCharges	0	USD
CY2020	btu	Provisionforequipmentloss Provisionforequipmentloss	0	USD
CY2019	btu	Provisionforequipmentloss Provisionforequipmentloss	83200000	USD
CY2018	btu	Provisionforequipmentloss Provisionforequipmentloss	66400000	USD
CY2020	us-gaap	Gain On Business Interruption Insurance Recovery GainOnBusinessInterruptionInsuranceRecovery	0	USD
CY2019	us-gaap	Gain On Business Interruption Insurance Recovery GainOnBusinessInterruptionInsuranceRecovery	91100000	USD
CY2018	us-gaap	Gain On Business Interruption Insurance Recovery GainOnBusinessInterruptionInsuranceRecovery	0	USD
CY2020	btu	Increase Decreasein Deferred Tax Asset Valuation Allowanceand Amortizationof Basis Difference Relatedto Equity Affiliates IncreaseDecreaseinDeferredTaxAssetValuationAllowanceandAmortizationofBasisDifferenceRelatedtoEquityAffiliates	-30900000	USD
CY2019	btu	Increase Decreasein Deferred Tax Asset Valuation Allowanceand Amortizationof Basis Difference Relatedto Equity Affiliates IncreaseDecreaseinDeferredTaxAssetValuationAllowanceandAmortizationofBasisDifferenceRelatedtoEquityAffiliates	18800000	USD
CY2018	btu	Increase Decreasein Deferred Tax Asset Valuation Allowanceand Amortizationof Basis Difference Relatedto Equity Affiliates IncreaseDecreaseinDeferredTaxAssetValuationAllowanceandAmortizationofBasisDifferenceRelatedtoEquityAffiliates	18300000	USD
CY2020	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	139800000	USD
CY2019	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	144200000	USD
CY2018	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	151300000	USD
CY2020	us-gaap	Investment Income Interest InvestmentIncomeInterest	9400000	USD
CY2019	us-gaap	Investment Income Interest InvestmentIncomeInterest	27000000.0	USD
CY2018	us-gaap	Investment Income Interest InvestmentIncomeInterest	33600000	USD
CY2020	btu	Markto Market Adjustmenton Pensionand Postretirement Plans Net MarktoMarketAdjustmentonPensionandPostretirementPlansNet	-5100000	USD
CY2019	btu	Markto Market Adjustmenton Pensionand Postretirement Plans Net MarktoMarketAdjustmentonPensionandPostretirementPlansNet	67400000	USD
CY2018	btu	Markto Market Adjustmenton Pensionand Postretirement Plans Net MarktoMarketAdjustmentonPensionandPostretirementPlansNet	-125500000	USD
CY2020	us-gaap	Reorganization Items ReorganizationItems	0	USD
CY2019	us-gaap	Reorganization Items ReorganizationItems	0	USD
CY2018	us-gaap	Reorganization Items ReorganizationItems	-12800000	USD
CY2020	btu	Derivative Instruments Not Designatedas Hedging Instruments Unrealized Gain Loss Net DerivativeInstrumentsNotDesignatedasHedgingInstrumentsUnrealizedGainLossNet	-29600000	USD
CY2019	btu	Derivative Instruments Not Designatedas Hedging Instruments Unrealized Gain Loss Net DerivativeInstrumentsNotDesignatedasHedgingInstrumentsUnrealizedGainLossNet	42200000	USD
CY2018	btu	Derivative Instruments Not Designatedas Hedging Instruments Unrealized Gain Loss Net DerivativeInstrumentsNotDesignatedasHedgingInstrumentsUnrealizedGainLossNet	18300000	USD
CY2020	us-gaap	Gain Loss On Sale Of Commodity Contracts GainLossOnSaleOfCommodityContracts	7100000	USD
CY2019	us-gaap	Gain Loss On Sale Of Commodity Contracts GainLossOnSaleOfCommodityContracts	1200000	USD
CY2018	us-gaap	Gain Loss On Sale Of Commodity Contracts GainLossOnSaleOfCommodityContracts	-700000	USD
CY2020	btu	Fresh Start Adjustment Fair Value Adjustment FreshStartAdjustmentFairValueAdjustment	8200000	USD
CY2019	btu	Fresh Start Adjustment Fair Value Adjustment FreshStartAdjustmentFairValueAdjustment	16600000	USD
CY2018	btu	Fresh Start Adjustment Fair Value Adjustment FreshStartAdjustmentFairValueAdjustment	26700000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	8000000.0	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	46000000.0	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	18400000	USD
CY2020	btu	Segment Reporting Information Adjusted Earning Before Interest Taxes Depreciation And Amortization SegmentReportingInformationAdjustedEarningBeforeInterestTaxesDepreciationAndAmortization	258800000	USD
CY2019	btu	Segment Reporting Information Adjusted Earning Before Interest Taxes Depreciation And Amortization SegmentReportingInformationAdjustedEarningBeforeInterestTaxesDepreciationAndAmortization	883000000.0	USD
CY2018	btu	Segment Reporting Information Adjusted Earning Before Interest Taxes Depreciation And Amortization SegmentReportingInformationAdjustedEarningBeforeInterestTaxesDepreciationAndAmortization	1387900000	USD
CY2020	btu	Segment Reporting Revenue Percentage SegmentReportingRevenuePercentage	1.000
CY2019	btu	Segment Reporting Revenue Percentage SegmentReportingRevenuePercentage	1.000
CY2018	btu	Segment Reporting Revenue Percentage SegmentReportingRevenuePercentage	1.000

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2019 Q4 Form 10-K Financial Statement

#000106472821000008 Filed on February 23, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$BTU PEABODY ENERGY CORP Stock $btu

2019 Q4 Form 10-K Financial Statement

#000106472821000008 Filed on February 23, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$BTU
PEABODY ENERGY CORP Stock $btu